Fentanyl test strips could lead to false sense of security, Health Canada warns

Fentanyl test strips don't always detect the presence of the deadly opioid and could give drug users a false sense of security, Health Canada is warning.

In an advisory issued Wednesday, the department said its drug analysis service did a "preliminary study" to compare "a fentanyl test strip product" used in communities against its own more sophisticated laboratory tests.

Demand for commercially produced test strips has boomed as recreational drug users and harm-reduction workers try to stop the rising number of deaths due to street drugs laced with fentanyl.

• Demand for fentanyl test strips booms but test is not widely available

The Health Canada study compared fentanylstrip test resultswith itsprofessional laboratory test resultson 70 samples of drugs. Most of the samples "containedchemically similar drugs (fentanyl and analogues with similar chemical profiles, such as carfentanil)," departmentspokesman Eric Morrissette told CBC News in an email Wednesday evening.

In 63 of thesamples,the test strips "accurately identified that opioids were present," he said.

But in three samples, the fentanyltest strips gave false negatives, indicatingno opioidswere present, when the lab tests indicated they were.

The stripsshowed false positives for opioidsin two cases, and gave "invalid results" in two others.

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AlthoughMorrissettecautioned that the results are "very preliminary" and that the sample size was very small, he said the fact that"there is a possibility for false negatives in a small number of instances ... suggests more research on this issue is needed."

The risk of a false negative is particularly concerning, because it could "lead to a false sense of security which may result in overdose or death," Health Canada's advisory said.

"This is particularly true for people who may choose to use drugs alone or without visiting a supervised [drug] consumption site where emergency help is immediately available."

The department "is urging Canadians to treat all illegal drugs as potentially contaminated," and to take precautions if using drugs, including never using them alone,going to a supervised consumption site whenever possible, and ensuring naloxone(a drug used to reverse overdoses) is available.

In its next phase of assessing fentanyltest strips, Health Canada plans to use them with a greatervariety and number of drug samples.

Morrissette was unable to immediatelyprovide the brand name of the fentanylteststrip product that was studied, or specify what kind of drugs were tested.

• 2,000% rise in street drug samples testing positive for fentanyl

But regardless of the brand, "Health Canada has not licensed any drug test strips as medical devices intended for drug-checking of illegal drug samples before consumption," Morrisette said.

However, provincial and territorial health ministries have the authority to distribute fentanyltest strips as a harm-reduction measure.

In British Columbia, clients at thesupervised consumption site Insitehave been allowed to use the strips to test their drugs. Drug users are not permitted to use them off-site in private homes or in the community.The Ontario governmentalso announced earlier in the fall that it would provide fentanyltesting strips "at all current supervised injection services and pop-up sites and will be evaluated for further distribution."